The aim of this proposal is to determine the covalent structure of the propeptides of Type I and Type II procollagen. The propeptides from the C-terminal region of the pro alpha l(I) and pro alpha 2 chain of Type I procollagen will be isolated and the complete structure of these peptides will be determine. Also, the structure of the N-terminal propeptide of the pro 2 chain synthesized by fibroblasts will be analyzed. In the case of Type II procollagen, initial experiments will focus on the structure of selected regions of the N-terminal and C-terminal propeptides. Special attention will be given to the cleavage sites at which procollagen peptidases cleave the molecule, to regions which contain interchain disulfide bonds, and to regions which contain carbohydrates.